This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In pre-hypertensive 4 week old animals, we documented major morphological differences in kidney-associated brown adipose tissue (KBAT) between genetic hypertensive rats (SHR) and normotensive strains (BN-Lx) and have shown that a quantitative measure of these morphological differences, average lipid droplet size, correlates with and appears to predict the level of hypertension. In order to obtain firm quantitative evidence of differences in mitochondria we propose to do EM analysis, including electron tomography, of both KBAT and interscapular brown adipose tissue (IBAT) from at least the two progenitors (SHR and BN-Lx) and possibly several derived recombinant inbred (RI) strains. Because the major underlying issue is the physical and functional relationship between lipid droplets and associated mitochondria, we also seek future tomographic studies to develop methods to evaluate cellular metabolism with lipid storage vesicles and associated functioning mitochondria. The results of these studies should have long-term relevance in defining new directions in studying the role of intracellular 3-dimensional relationships to complex disorder phenotypes through altered cellular metabolism and function.